Tungstate Intercalated NiFe Layered Double Hydroxide Enables Long‐Term Alkaline Seawater Oxidation

Abstract

Renewable electricity‐driven seawater splitting presents a green, effective, and promising strategy for building hydrogen (H2)‐based energy systems (e.g., storing wind power as H2), especially in many coastal cities. The abundance of Cl− in seawater, however, will cause severe corrosion of anode catalyst during the seawater electrolysis, and thus affect the long‐term stability of the catalyst. Herein, seawater oxidation performances of NiFe layered double hydroxides (LDH), a classic oxygen (O2) evolution material, can be boosted by employing tungstate (WO42–) as the intercalated guest. Notably, insertion of WO42− to LDH layers upgrades the reaction kinetics and selectivity, attaining higher current densities with ≈100% O2 generation efficiency in alkaline seawater. Moreover, after a 350 h test at 1000 mA cm−2, only trace active chlorine can be detected in the electrolyte. Additionally, O2 evolution follows lattice oxygen mechanism on NiFe LDH with intercalated WO42−.

La doping greatly enhances electrochemical alkaline seawater oxidation over Ni(OH)2 nanosheet

“…S5 † show that the downward trend of La-Ni(OH) 2 /NF is greater than that of Ni(OH) 2 /NF, representing the faster reaction kinetics of La-Ni(OH) 2 /NF. 42 These findings suggest that La-Ni(OH) 2 /NF exhibits remarkable electrochemical performance for OER in 1 M KOH.…”